Case Studies

Case Study 1

Location – London

Description – Investigation into source of water in flooded basement

Case Environmental was asked to determine the source of water flooding a basement of one of the largest demolition sites in London.  The flood water had damaged several electricity sub-stations which the electricity company had to isolate.  The electricity company had made the assumption that water used for dust suppression had been responsible for causing the flooding.   There was the threat of legal action being taken against the demolition company to recover costs incurred due to the damage.

Case Environmental investigated the site and by using water sampling, site observations and local knowledge was able to prove that the source water was not associated with the water used for dust suppression.

No further action was taken against the client by the electricity company.

Case Study 2

Location – East Devon

Description – Investigation into private drinking water and sewage assets at a domestic property

Case Environmental was contacted by a purchaser of an old farm in East Devon.  The property had been empty for several years and as it was an executor sale there was very little information regarding the existing water and sewage assets.

Upon investigation a poorly constructed spring was identified as the main water source.  A borehole was also present but after drilling it had suffered structural problems and was never used.  The spring was close to the point of surface discharge from an existing septic tank, had insufficient vermin protection and took a long time to recharge after abstraction.  In addition several tanks were found connected to the spring – these were in a very poor state of repair and due to the configuration, would allow for stagnation during storage.  At the point of use no water treatment was fitted.

After further investigation a second, abandoned source was found.  This was a well close to the house last used in the 1950s.  It had been decommissioned and capped but still contained water and appeared in relatively good order.  A water engineer was instructed to open-up the well and test-pump the water to assess recharge rate and quality.  The well was found to be capable of supplying a good yield of high quality water.  Case Environmental wrote a specification for the formal improvement and reinstatement of the well to provide drinking water to the property.  This included specifying the appropriate treatment based on the chemical and microbiological characteristics of the water.

The septic tank serving the property was found to be significantly undersize for the intended future use of the property.  Of further concern was the septic tank discharge, which flowed directly to surface into a wooded embankment; not only was this illegal, it also presented a considerable environmental health hazard.  Case Environmental provided a specification to decommission the septic tank and replace it with a modern, compliant system.

Case Study 3

Location – Offshore island in Atlantic

Description – Remediation of well used as septic tank

During refurbishment of a tenanted residential property a customer of Case Environmental discovered what appeared to be a well repurposed as a septic tank.  Case Environmental investigated and confirmed that the asset was a well being used as a septic tank; of note, it still featured the original hand pump.

This presented a considerable pollution risk to the island aquifer and required immediate action to remove the pollution.  Case Environment wrote a specification for the remedial works and a local contractor undertook the necessary work.  The well was found to be around 10m deep and after emptying and cleaning was decommissioned by filling the well with inert media to replicate existing ground-conditions.  The top structure of the well was capped to ensure no further pollution could occur.

Case Study 4

Location – Historic house, London

Description – Heavy metal pollution of rain water used for irrigation of a kitchen garden

Case Environmental was asked to provide advice regarding the results of a recent water test taken by a company who had an installed a rainwater irrigation system to a historic house in London.  The water had been tested and found to contain extremely high levels of lead and also have a low pH (acidic).  The water was being used to irrigate a kitchen garden and due to the low pH there was increased potential for plants to absorb lead.

Case Environmental investigated the whole system and identified that the source of the lead was a combination of acidic rainwater being in contact with lead used for roofing and rain water goods.  Due to the historic nature of the house it was not possible to eliminate the lead from the system so an alternative solution had to be considered.  Due to expense (and associated maintenance requirements) treatment was not deemed an option.  Looking at the surrounding area an abandoned historic well previously used to supply the whole estate was found.  The water quality in the well was tested and found to be equivalent to drinking water quality.  Case Environmental wrote a specification to abstract water from the well and use it in preference to the rain water.  The rain water would return to land drainage as it had done previously and ultimately recharge the local aquifer. 

Case Study 5

Location – Somerset

Description – Consultancy advice for newly installed borehole water supply

Case Environmental was contacted by a concerned house owner who had recently paid a considerable sum for a new borehole water supply.  Since installation the borehole and associated treatment had proved to be unreliable and expensive to maintain.  The service provided by the contractors had also been poor.

Case Environmental visited the site and quickly identified that the borehole was not built to low risk standards and was in fact within 20m of a store of farmyard livestock waste and 10m from an un-capped below-surface abandoned water source – this was in contravention of Environment Agency guidance.  It was also identified that the treatment fitted was incorrectly specified and also partly responsible for the high maintenance costs.

The installing contractor was supplied a copy of the Case Environmental report and with the impending threat of imminent legal action repaid the customer the full costs.  This allowed the customer to install a low risk borehole with correctly specified treatment.